Congrats on your find. As stated these guys are blast to ride and comfort wise I don't think they can be beat. I actually found long hours on this bike more comfortable than riding in a car and have done day trips well in access of 10 hours. The main upgrades you really need to do IMHO is replace/upgrade the fuse holders, (including the main fuse, ( upgrade it to a blade type Maxi-fuse). Replace the clutch slave with a new one, upgrade the clutch to either a Barnett or one of Skydoc_17's upgrade kits. Replace the brake and clutch lines with quality brake certified stainless lines and While your at it I definitely recommend de-linking ** the brakes. I have not done the caliper upgrade because I found that after de-linking the brakes, the front brakes were fully capable of locking up the front wheel and causing the bike to do a nose stand lifting the back wheel clean off the ground ( I would say any more brake power than that is just wasting money ). Ignition switch issues common to the second gens are not an issue with the first gen so I would not bother messing with the ignition, If your adding lights etc go through an add on relay switch. There are various ways to wire it up depending on how you want the add on's to function. I would add a manual over ride switch for the cooling fan (Handy to have in stop and go traffic in hot weather or in case the fans thermal switch should fail not that it ever really happens much).
Additional upgrades such as progressive springs are a nice touch (and many like the upgrade, (myself included) but depend largely on what type of ride characteristics you want from the bike.
** de-linking the brakes - the left front and the rear caliper are linked together. This great on hard dry road surfaces but can be an issue in loose surface material were you would not normally use the front brake and has cause front wheel related wipe outs. By de-linking your are removing the left front caliper from the rear master and pairing it up with the right front caliper this not only gives you independent front and and rear wheel braking control but increase front wheel braking.